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Fracture behaviour of large diameter pipeline girth welds: Effect of weld metal yield strength and defect interaction. Final report

Abstract

Weld quality standards establish allowable defect levels for many possible combinations of defect geometries, location, and frequency of occurrence (multiple/neighbouring defects). When non-destructive examinations reveal multiple defects, a defect recategorization procedure is applied to determine whether the multiple/neighbouring defects will interact. The existing interaction rules are based on linear elastic fracture mechanics calculations and have been applied for general use. These rules are not necessarily applicable for pipe line girth welds since girth weld failure behaviour differs substantially from linear elastic behaviour. The objective of the work was to obtain information on the failure behaviour of girth welds containing two coplanar fatigue pre-cracked defects. The results were then correlated with tests containing a single crack in order to determine the engineering significance of existing interaction rules under elastic-plastic and plastic fracture conditions. Experimental results showed that the failure characteristics of a defective girth weld is very sensitive to crack size and the degree of weld metal yield strength overmatching and overall failure strains can be greater on the overmatched welds. The comparison of samples with single and two coplanar cracks found that defect interaction is a complex function of the level of yield strength mis-match, toughness, defect size and the  More>>
Authors:
Publication Date:
May 24, 1994
Product Type:
Technical Report
Report Number:
AGA-95006553
Reference Number:
SCA: 022000; 420205; 360101; PA: EDB-95:050111; SN: 95001327667
Resource Relation:
Other Information: PBD: 24 May 1994
Subject:
02 PETROLEUM; 42 ENGINEERING; 36 MATERIALS SCIENCE; PIPELINES; FRACTURE MECHANICS; CRACK PROPAGATION; PIPES; YIELD STRENGTH; WELDING; PIPE JOINTS; ELASTICITY; WELDED JOINTS; PROGRESS REPORT; FATIGUE; STRAINS; TENSILE PROPERTIES; CHARPY TEST; CRACKS; NONDESTRUCTIVE TESTING; DEFECTS; STRESS INTENSITY FACTORS; 022000; 420205; 360101; TRANSPORT, HANDLING, AND STORAGE; TRANSPORT AND STORAGE FACILITIES; PREPARATION AND FABRICATION
Sponsoring Organizations:
American Gas Association, Inc., Arlington, VA (United States)
OSTI ID:
10119827
Research Organizations:
Ghent Rijksuniversiteit (Belgium). Lab. Soete
Country of Origin:
Belgium
Language:
English
Other Identifying Numbers:
Other: ON: UN95006553; CNN: Contract PR-202-011; TRN: 95:002528
Availability:
American Gas Association, 1515 Wilson Blvd., Arlington, VA 22209 (United States)
Submitting Site:
OSTI
Size:
115 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Denys, R M. Fracture behaviour of large diameter pipeline girth welds: Effect of weld metal yield strength and defect interaction. Final report. Belgium: N. p., 1994. Web.
Denys, R M. Fracture behaviour of large diameter pipeline girth welds: Effect of weld metal yield strength and defect interaction. Final report. Belgium.
Denys, R M. 1994. "Fracture behaviour of large diameter pipeline girth welds: Effect of weld metal yield strength and defect interaction. Final report." Belgium.
@misc{etde_10119827,
title = {Fracture behaviour of large diameter pipeline girth welds: Effect of weld metal yield strength and defect interaction. Final report}
author = {Denys, R M}
abstractNote = {Weld quality standards establish allowable defect levels for many possible combinations of defect geometries, location, and frequency of occurrence (multiple/neighbouring defects). When non-destructive examinations reveal multiple defects, a defect recategorization procedure is applied to determine whether the multiple/neighbouring defects will interact. The existing interaction rules are based on linear elastic fracture mechanics calculations and have been applied for general use. These rules are not necessarily applicable for pipe line girth welds since girth weld failure behaviour differs substantially from linear elastic behaviour. The objective of the work was to obtain information on the failure behaviour of girth welds containing two coplanar fatigue pre-cracked defects. The results were then correlated with tests containing a single crack in order to determine the engineering significance of existing interaction rules under elastic-plastic and plastic fracture conditions. Experimental results showed that the failure characteristics of a defective girth weld is very sensitive to crack size and the degree of weld metal yield strength overmatching and overall failure strains can be greater on the overmatched welds. The comparison of samples with single and two coplanar cracks found that defect interaction is a complex function of the level of yield strength mis-match, toughness, defect size and the required level of performance (or applied strain). The present data base was not extensive enough to creat a simple model capable of predicting the influence of all these parameters on defect interaction.}
place = {Belgium}
year = {1994}
month = {May}
}